Attachment for vibratory screens



Feb. 23, 1954 F. K. BETTS m 2,670,079

ATTACHMENT FOR VIBRATORY SCREENS Filed Sept. 20, 1949 2 Sheets-Sheet l w WW Feb. 23, 1954 F. K. BETTS m 2,670,079

ATTACHMENT FOR V IBRATORY SCREENS Filed Sept. 20, 1949 2 Sheets-Sheet 2 J4 I Z: 4 714 13 56 WW "HIHIWW 5a 0: Z 1

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mfinmbiww Patented Feb. 23, 1954 UNITED STATES PATENT OFFICE ATTACHMENT FOR VIBRATORY SCREENS Fred K. Betts III, Harrisonburg, Va.

Application September 20, 1949, Serial No. 116,827

1 Claim. 1

This invention relates in general to screening mechanisms, and more particularly to an attachment for a vibratory screen employing a plurality of removable graduated screens for grading or sifting granular or pulverant material.

As the screens in vibratory screening mechanisms for grading granular material are subject to particularly harsh use in grading the granular material and frequently require replacement or repair, and as it is frequently necessary to change the sizes of wire mesh screen in accordance with the grading desired, from a practical point of view it is important that the individual screens be readily removable from the outer screen housing frame. Conventionally, the screens are provided with framing members which are removably secured to the side walls of the outer screen housing frame, generally by mounting bolts extending through the screen members and through corresponding apertures in the side wall of the screen housing frame, or by pivotal supports retaining the screen frames against supporting ledges or lugs extending inwardly from the sides of the housing or against the sides of the housing frame, the pivotal clamping members having bolts extending through the side walls adapted to be secured outwardly of the screen housing frame by means of lock nuts or the like. These bolts must generally be spaced not more than six inches apart longitudinally of the screens because of the severe strain to which the screens are subjected during vibration. It will be apparent, therefore, that such screen mounting devices involve considerable losses in time and labor in removing and replacing the individual screens within the housing frame, as each of the bolts must be individually uncoupled from its lock nut high degree of tensioning of metal'framed sizing screens. I

Another object of the present invention is the is the 7 provision of novel means for removably mounting a plurality of sizing screens within a vibratory screen housing, which means are readily adaptable to release the vibratory screens by manipulation of means disposed externally of the screen housing to permit withdrawal of the screens from the housing.

Another object of the present invention is the provision of novel keeper means for releasably securing angle iron framing members of sizing screens relative to the sides of the sizing screen housings, wherein the keeper means are readily operable from externally of the screen housing, which facilitate a high degree of tensioning of the sizing screens when moved into clamping position, and which are operative to draw a flange of the framing members of the sizing screen flush against the side wall of the housing.

Other objects, advantages, capabilities of the present invention will become apparent from the following detailed description'taken in conjunction with the accompanying drawings, in which only a preferred embodiment of the invention is shown.

In the drawings: 7

Figure 1 is a side elevation of a vibratory screening mechanism for grading or sifting granular or pulverant material, embodying the present invention, only a portion of the stationary supporting frame and feeding and discharge chutes being shown;

Figure 2 is a top plan view of the vibratory screening mechanism shown in Figure 1;

Figure 3 is a partial vertical sectional view of the lower or discharge end of the grading screen and a portion of the housing frame, taken alon the lines 3-3 of Figure 2;

Figure 4 is a vertical transverse section through the vibratory screening mechanism, taken along the lines 4-4 of Figure l and Figure 5 is a vertical section of the clamping means and a grading screen, illustrating the cooperative association of the members to effect clamping of the sizing screen within the housing, taken along the lines 5.5 of Figure 2.

Referring to the drawings, in which like ref-:

erence characters designate corresponding parts throughout the several figures, the reference character l0 designates a stationary support formed of suitable material such as angle iron members or the like, having two horizontal, laterally spaced rail elements ll upon which the vibratory screening device is mounted. Between the horizontal spaced rails H of the support II isdisposed a vibratory screen housing frame,

generally indicated at I2, of substantially rectangular horizontal cross section adapted to house a plurality of vertically spaced grading screens I3, I4 and I5 of wire mesh fabric. The rectangular screen housing frame I2 is open along the top and bottom thereof and has side walls I6, IS, a feed end wall I! having transverse slots I'I therein adapted to permit ingress and egress of the wire mesh screens I3, I4 and I5, and a discharge endwall Illhavirlg transverse discharge openings I9 therein, the bottom of each of the openings I9 being flush with the wire mesh screens to permit discharge of granular material retained thereby by gravitational forces.

A feed chute 20 disposed above'the open top of the housing frame I2 is provided itowcouple the granular substance into the housing frame I2, and extends to a suitable-hopper or the like Jably of angle iron bars, the edge supporting brackets 40 .on-theside walls I6, I6 of the housing I2 being'disposed in planes descending from .-.thezfeed..end=zwall I1 to the discharge end wall I8 and forming an angle of approximately fifteento eighteen -degrees with the horizontal.

(not shown) for retaining the mixed granular material. Likewise, discharge chutes 2I are coupled to each of the discharge. openings I9,in the discharge endwall I 8 to couplethe graded granularmaterials retainedby, each of thezscreens I3, I4 and 15 into suitable containers .(not shown).

A bottom discharge chute 22 islikewiseprovided for coupling .the finest grades of. granular, material passed by each of the grading screens .13, I4 and I5 into another suitable containerdisposed belowthe device.

'Eachof the screens 13, I4 and I5 are of progressively increasing, mesh so that the larger granular, material .willbe retained by the upper screens, as I3 and I4, anddischarged into their appropriate containers, while the finer granular substances will be passed through to subsequent grading screens, such as screen I5,' or through all of .the grading screens into the. fine granular substance discharge chute 22. The mesh of wire screens, as generally. used the art, is understood to referto the number. of openings per,

such as for, examplemetallicdrums 26. fixedly mounted to the rails II, surrounding annular rubber blocks 21 in which metallic lugs 28 bolted to the sides 16 of the housing. I2 are disposed. In this manner a considerableamount of oscillatory rocking or vibratory action-ean-be imparted to the screen housing, I2. Preferably, there are fourof these resilient supporting bearings arranged in pairs on eachside of the housing I2.;-

Any suitable form of. vibratingmechanism may be used to. vibrate the housingmemberi! land the screens I3, I4 and I5. Preferably, however, the conventional unbalanced shaft type of vibrat ing mechanism is employed, comprisingamunbalanced or eccentricshaftBQ journaled hearings 3| on the side Walls l6, .IS' of the housing I2, extending through bearings 32 ,fixedly mounted on the horizontal spaced rails I I of. the

support. I0, and, having a pulley-.33 keyed to one end of the shaft 30. The .pulley- 33 maybe intercoupled by means of belt.34.;to adrive pulley35 on the shaft of. a. Suitable, electriomotcr, ,of any vcommercially.available type, .mounted, on. .a supportingv bracket. 31., on,the. fixed support: :I 0.

the bearings 25, of conventional construction,

ill

The grading screens 13, I4 and I5 are constructed of conventional wire mesh fabric, stretched betweena. substantially rectangular screen frame M, the side framemembers 42, 42 and theencl framemember .43 disposed at the feeding endof the housing. I2 being constructed of angle iron bars, and thelower. discharge end frame member 44. being. constructed, of. a flat metallic strap. The. edges. ofthe Wire mesh fabric may be rigidly. clamped to the lateralflanges of the frame members 4I-by,.m eans of suitablelengths of fiat metallic straps .45 retained against the lateral flangev of the frame members 42,. 42', 43and 44 by means of. bolts andnuts 46 extending therethrough for. clamping the wire .mesh fabric between theladiacent surfaces.

Means areprovided extending. through apertures in'the sides. I6, 16?. of thehousing frame I2 which may bev operated. from externallyof the housing. to .clampa surface .of the angle iron frame members 42, .42.and 43 against theadja cent sidesof the housing frame and tension the grading. screenlaterally. These clamping'means compriseright angular keeper elements 50 having an arm. 5I adapted. to.. extend through suitable slots. 52 inthe sidewalls -.I 6, I6. of the-housing I 2, and a downwardly depending locking flange 53 adapted to 'abutagainst the inwardly disposed faceoftheupright flanges on theangle iron frame members 42 and 42. The slots 52 and side walls. I6, I6 of the housing I2 are disposed with their lower edges approximately aligned horizontally with. the .uppermost point on the upright flangesof. the angle iron frame members. 42, 42 Suitable struck. edges. or lugs. 54, or other like; fiaredportions, are provided at the outer ends. of the arms SI of the keeper elements 50 formed.-bypeeping or the. like to prevent the keeper elements 50 from :being withdrawn into the inside of. the; Vertical; slots housing I2 through theslots 52. 55: are provided-in the keepers 50, extending w.through= the-arm 5I, adapted to receive-wedge-' shaped locking members 56 therethrough.

The wedge members 56 taper upwardly to an apex indicated ati56, and are adapted to be-insertedinthe slots 55- and driven upwardly 'until the-inwardly disposed face 57-01- the-wedgeili abuts against the outer face of the side wall I6 or I6, the outerinclined surface 58 of the wedge 56 abutting against the rear edge of the slot 55 ing dance 53 .ofthekeeperml towardthe adjacent; If theside,

side walls I6, I6 of the housing I2. wall ,I ,6, .I 6', of the-housing: i2 relativelythin,

a suitable apertured spacing block 59 may be disposed over the arm of the keeper 50 and the inner surface 51 of the wedge56 disposed against the washer 59. Suitable apertures 60 are formed in the wedge 56 spaced longitudinally thereof'to' permit a retaining pin to be inserted therethrough when the wedge is driven through the aperture 55 to lock thebracket and grading screen in place.

It will be apparent that the removable screen clamping means may be readily adjusted to clamping or releasing condition from externally of the grading screen housing I2 in a very simple manner. The right angle keeper elements 50 are formed of substantial width and thickness so that only four or five of the elements spaced twelve to eighteen inches apart are necessary for effective clamping of the grading screens.

In operation, the keeper elements are pushed inwardly of the side walls I6, I6 until the retaining lugs 54 engage the apertures 52 in the side walls of the housing I2, and the grading screen, such as screen I3, is inserted into the housin I2 through the transverse slots IT in the feed end wall I1 until the grading screen is wholly disposed within the housing with the frame members 42, 42 and 43 supported on the edge supporting brackets 40. As the discharge end frame member 44 of the grading screen frame 4!, which is disposed in the direction of insertion of the screen into the housing I2, is only a fiat metal strap 44, the upright flanges of the angle iron screen frame members 42, 42 will slide between the inwardly disposed face of the locking flange 53 on each of the keeper elements 50 and the adjacent inner surface of the side walls I6, I6 of the screen housing. The ends of the arms 5I of the keeper elements 50 are then withdrawn through the apertures 52 in the side walls I6, I6 and the apices 56' of the wedges 56 inserted in the slots 55 of the elements 50. The wedges are then driven upwardly within the slots as far as possible, the inner surface 51 of the wedge bearing against the outer surface of the side walls I6, I6 and the inclined surface 58 of the wedge engaging the rear of the slot 55 to cam the keeper 50 outwardly of the housing I2 and draw the screen frames 42, 42 toward their adjacent side walls l6, I6.

It will be noted that the forces on the keeper elements 56, apparent from inspection of Figure 5, resulting from the camming action of the wedges 56 in slots 55, likewise tend to cant the angular keeper element in a clockwise direction as viewed in Figure 5, to dispose the lateral and upright flanges of the right angle frame members 42, 42 against the adjacent faces of the edge supporting brackets 40 and side walls I6, I6, respectively. An extremely secure clamping of the frame member M of the grading screen is thus obtained, in which both flanges of the angle iron frame members are rigidly clamped against corresponding faces of supporting members, and the side frame members 42, 42' spread outwardly laterally of the housing I2 to effect a high degree of tensioning of the grading screens.

To remove any one of the grading screens I3, I4 and I5 from the screen housing I2 for repair or replacement purposes, the operator need only withdraw the wedge 56 from its slot 55 in the horizontal arms of the keeper elements 50 and push the elements inwardly of the housing side walls l6, l6 as far as they will go to effect withdrawal of the grading screen from the housing. It will be apparent that a considerable saving in time and labor is thus effected in removing and replacing the grading screens in the above recited manner, as removal of nuts and bolts or the like from the side walls of the housing and the framing members of the grading screens is no longer necessary. Likewise, no means for access to the inside of the screen housing I2 need be provided, as the keeper elements 50 are never entirely withdrawn from the associated side wall apertures 52.

It will be apparent that a novel vibratory screening mechanism and clamping means, therefore, have been provided, in which removal of the individual grading screens is greatly facilitated, as the clamping and unclamping of the grading screens within the screen housing is effected entirely from without the housing. Likewise, a simple, inexpensive, and highly durable construction is provided, in which fewer clamping devices are necessitated for the grading screens, and by which the screens may be tensioned laterally and positively clamped against right angularly disposed supporting surfaces within the screen housing.

While but one specific embodiment of the invention has been particularly shown and described, it is distinctly understood that the invention is not limited thereto, but that various modifications may be made in the invention without departing from the spirit and scope thereof, and it is desired, therefore, that only such limitations shall be placed thereon as are imposed by the prior art and are set forth in the appended claims.

What is claimed is:

A vibratory screening mechanism for grading granular materials and the like comprising a housing having opposed vertical side walls and a screening unit, means on said side walls forming supporting ledges for said screening unit at opposite sides of said housing and projecting inwardly at right angles from said side walls, said screening unit comprising a screening medium bounded by angle irons having transverse flanges connected to said screening medium adapted to seat on said ledges and upright flanges for engaging the side walls of said housing, clamping means intercoupled with said housing for drawing said angle irons against said side walls and thereby stretching and securing said screening medium, said clamping means comprising a plurality of rigid hooks located in spaced relation longitudinally along each of said side walls, said hooks each being formed of bars of substantially rectangular cross section bent into right angular shape along a transverse axis substantially midway of its length to define an arm extending through the side walls of said housing in substantially perpendicular relation thereto and a depending finger extending at right angles to said arm and parallel to said side walls in overlying and engaging relation with the upright flanges of said angle irons to draw the upright flanges of said angle irons against the side walls of said housing, each of said arms having a vertical slot extending therethrough, and upwardly converging wedge-shaped members disposed externally of said housing and extending through said slots, said wedge-shaped members bearing against said housing side walls for camming said hooks outwardly of said housing and canting the depending fingers of said lrooks downwardly to lock the upright flanges of said angle irons in intimately contacting relation throughout with said housing side walls and said transverse flanges in intimately con- 

